The commercial electric power generating nuclear reactor has become an important means of meeting the power requirements of present day society. In designing such nuclear reactors, every effort is made to prevent accidental discharge of even trace amounts of radioactive materials into the environment. The safety systems which are used to prevent improbable yet postulated accidents must be efficient and operate with absolute reliability.
Most present day nuclear reactors employ water as a coolant for the reactor. In designing such systems, provision must be made for a loss-of-coolant accident, however remote the possibility of such an occurance. In the unlikely event of such an accident, the nuclear plant containment system will contain any radioactive material released from the reactor vessel itself, as well as withstanding any pressure surges in the system. The containment system itself, of course, isolates the entire nuclear system from the environment. Following a major loss-of-coolant accident in a water cooled reactor, hydrogen may be generated within the reactor containment system by the mechanisms of radiolysis, zirconium-water reaction, and by corrosion of the metal elements. The containment system atmosphere will be radioactive and necessarily sealed within the system for an extended period of time until this atmosphere can be cleansed or its radioactivity otherwise reduced, to prevent the release of any radioactive contamination to the environment. Provision must therefore be made to limit the hydrogen concentration contained in the containment system, to avoid any dangerous buildup of hydrogen gas.
Hydrogen gas is also utilized in a number of other systems typically associated with water cooled reactors, and is particularly used in removing fission product gases from an interface with the primary coolant water whereby hydrogen carrier gas is used to strip the fission products from the coolant. The use of hydrogen gas in a water coolant system is also shown in U.S. Pat. No. 3,362,883, owned by the assignee of the present invention.